SPIN BOLDAK, Afghanistan (Reuters) - At least 13 civilians were killed in a bombing raid by U.S.-led forces battling the Taliban, an Afghan official said on Friday, bringing to 70 the number of such deaths reported this week.

The rising toll of civilian casualties will put further pressure on President Hamid Karzai, who warned this week of serious consequences for all if the bloodshed did not stop.

The civilians were killed in bombing on Tuesday night in the Maroof district of southern Kandahar province, near the border with Pakistan, said Janan Gulzai a provincial assembly member.

"I saw all the victims are civilians," Gulzai who was a member of a government team investigating the incident, told Reuters.

"We cannot accept the killing of Afghan civilians by anyone."

The civilians were traveling in three cars along the same stretch of road as coalition troops near the town of Spin Boldak when the troops came under Taliban fire, said Ghulam Farooq, a resident of the area.

The 13 civilians were killed when coalition warplanes were summoned to bomb the area while the Taliban escaped, he said.

A spokesman for the U.S. military said he had no information about the report and would check.

Protesters -- angry over civilian deaths reported in the western province of Herat and in the east of the country -- called this week on Karzai to quit, saying he was powerless to stop the killing.

Several hundred people staged another anti-U.S. and anti-Karzai protest on Friday over the civilian deaths in the east, residents said.

They briefly blocked a road where a convoy of the coalition forces was passing, but police dispersed the crowd and the protest ended peacefully.

The deaths in Herat, an area not known as a Taliban stronghold, prompted many Afghans to reject initial reports from U.S.-led coalition forces that the dead were 136 Taliban.

The Western military are inquiring into that incident, where Afghan officials say 51 civilians were killed.

While the protests over civilian casualties have been mainly small, government officials, NATO and analysts all warn that a steady stream of such deaths will inevitably erode support for Karzai and the war against the Taliban, who were driven from power in 2001.

Popular anger over civilian deaths caused by Western troops' anti-militant operations has been directed at Karzai, who is already facing criticism over a lack of development, rampant corruption and this year's surge in violence.

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